PREMATURE BOLTING OF ONION (ALLIUM CEPA L.) IN THE ARID TROPICS OF THE SUDAN

In the arid tropics of the Sudan, the common onion (Allium cepa L.) is grown as an irrigated early and late winter crop.
The early crop is sown in August-September, transplanted 6–8 weeks later and harvested during January-March.

The late crop is transplanted during November-January and harvested in May-July.
Part of the late crop is usually stored.
A high percentage of premature bolters is observed in the bulb crop of the local Sudanese red-skin open-pollinated type grown from seed or from transplants.
Randomized block field experiments were conducted over 3 years to study the effect of sowing dates spread over the period August-February at monthly intervals.
The crop was direct-sown on both sides of ridges and later thinned.

The bolting percentage was highest from the early sowings (70–80%) and decreased markedly with later sowing dates (10%).

In the early planting about 40–50% of the bolting plants produced single seed-stalks and about 20–50% produced more than one seed-stalk.
Splitting decreased with delay in the sowing date.
Percent split bulbs ranged between 35 in the early plantings and 10 in the late plantings.
Non-bolting and non-splitting bulbs are being selected for bolting resistance.

IV Africa Symposium on Horticultural Crops

A. A. Abdalla, Gaafar M. El Hassan

https://doi.org/10.17660/ActaHortic.1977.53.2